Shanghai authorities said they have started retrieving dead pigs from the water near the border between Shanghai and Zhejiang province.

Last week, a large number of dead pigs were found floating down the Huangpu River. The pigs are thought to have been dumped in Jiaxing, Zhejiang province.

So far, the number of carcasses retrieved from the Huangpu River has exceeded 7,500, according to local authorities.

The retrieved carcasses have been sent to biological treatment stations to avoid potential hazards.

The city government is also closely monitoring the water quality. No hazardous bacteria have been found in the tests, according to Xu Wei, a spokesman for the Shanghai government.

Xu said the government is also boosting meat inspections in local supermarkets and butcher shops.

The Ministry of Agriculture has sent a special working team to supervise the investigations.